"She's always been very, very healthy. She's still got time for three more husbands after me," Clinton says, laughing. "I think she'll live to be 120. Whenever I am stubborn in her constant quest at my self-improvement, she refers to me as her first husband."

Jokes aside, Clinton talked about the possibility of a Hillary Clinton 2016 run in relation to the realities of aging and being "consumed with the third part of their lives."

"You reach a certain point in life when every day is a gift," Clinton said. "So your calculations aren't the same as they were when [you] were younger."

The chat shed some light on the former First Couple's ever-evolving relationships with each other, Washington and aging. To hear more -- and to hear what keeps the Clintons young -- watch the video above.